Transcriptome analysis of injured muscle identifies new candidate genes for satellite cell growth and myofiber formation during early muscle regeneration.

Abstract

Objective: : The self-repair capacity of skeletal muscle arouses interest in studying satellite cell activity and myofiber formation. The major molecular networks of satellite cell activity have been extensively studied. However, the mechanism by which micro-environmental factors regulate satellite cell activity for early muscle regeneration still remains poorly understood.

Methods: : Hematoxylin and eosin (HE) staining and immunofluorescence for embryonic myosin heavy chain (eMyHC) were performed on control and injured muscle samples at 12-, 24-, 36-, 48-, 60-, 72-, and 84-hour post-injury. Additionally, eMyHC immunofluorescence was conducted on muscle samples collected 96 hours post-injury from three mice. RNA sequencing (RNA-seq) and quantitative PCR (qPCR) were performed on samples from 24 mice, including controls and samples at 12-, 24-, and 84-hour post-injury.

Results: : In this research, 516 immune-related and 177 hormone response-related genes were up-regulated significantly. Further, statistical analysis indicated that the number of differentially expressed genes (DEGs) between up- and down-regulated immune system-related DEGs was similar with that of hormone response-related DEGs. Notably, p53 signaling pathway was significantly enriched throughout early muscle regeneration. Based on patterns of crucial myogenic genes expression, 326 and 320 candidate genes related to satellite cell growth and myofiber formation were obtained, respectively. Furthermore, through interaction network analysis, 41 immune factors, including S100a9，Csf3r，Cxcl3，Ppbp，Ccl3，Il1rn were found, which may regulate satellite cell activation, migration and proliferation. Likewise, 16 cell adhesion factors (Col1a2, Cdh2, Thbs2, etc.) may be involved in myofiber formation.

Conclusion: : This study leveraged transcriptomic analysis to uncover key candidate genes and biological processes involved in early muscle regeneration. These findings enhance our understanding of the molecular mechanisms underlying muscle repair and offer insights for future therapeutic strategies.